1. Field of the Invention
The present invention relates to an ink cartridge for supplying ink to an inkjet head of inkjet recording apparatus for ejecting ink to thereby perform printing.
2. Description of the Related Art
An ink cartridge is to supply reserved ink to an ink-jet head of inkjet recording apparatus. The ink supplied from the ink cartridge is distributed into a plurality of pressure chambers by the inkjet head, which selectively applies pulsed pressure to the pressure chambers so as to eject the ink from nozzles. The ink cartridge is removably attached to the inkjet head. When all the ink reserved in the ink cartridge is used up, the ink cartridge is replaced by a new ink cartridge reserving ink, and then disposed of by a user.
As an example of such an ink cartridge, there is known an ink cartridge in which a packing, a valve and a spring are provided in an ink channel communicating with the outside (see JP-A-2001-328279 (FIG. 1)). When the ink cartridge is not attached to the inkjet head, the valve is urged onto the packing by the spring so as to close the ink channel. When the ink cartridge is attached to the inkjet head, the valve is pressed to leave the packing by an ink supply needle communicating with the inside of the inkjet head, so as to open the ink channel. According to this ink cartridge, there is no fear that the ink reserved in the ink cartridge leaks out when the ink cartridge is not attached to the inkjet head, while the reserved ink is supplied to the inkjet head when the ink cartridge is attached to the inkjet head through the supply needle.
JP-A-2001-113723 (FIG. 4., etc.) discloses an ink cartridge having a valve and a spring to selectively change over from disconnection to connection or from connection to disconnection between an ink chamber for reserving ink and the outside. In this ink cartridge, a cylindrical packing forming an insertion path of an ink supply needle is pressed into an ink supply port for securing communication between the ink chamber and the outside. An ink guide chamber is formed on the ink chamber side by the cylindrical packing. The valve and the spring for urging the valve to keep elastic contact with the cylindrical packing are disposed in the ink guide chamber.
When the ink cartridge is attached to inkjet recording apparatus, the ink supply needle passes the insertion path of the cylindrical packing and abuts against the valve. Thus, the valve is moved toward the ink chamber so that an ink channel is formed between the ink chamber and the ink supply needle. In this event, the inner circumferential surface of the insertion path of the cylindrical packing abuts against the outer circumferential surface of the ink supply needle so that ink in the ink chamber can be prevented from leaking from the insertion path of the cylindrical packing. On the other hand, when the ink cartridge is detached from the inkjet recording apparatus, the valve is urged by the spring to elastically abut against the cylindrical packing. Thus, the valve is seated on the cylindrical packing so as to close the insertion path. As a result, the ink in the ink chamber can be prevented from leaking to the outside through the insertion path.